System and method for cancelation of internally generated spurious signals in a broadband radio receiver

Abstract

Lossless digital cancelation of internally generated spurious products within a signal receiver system is provided. In embodiments, the receiver system generates reference frequencies corresponding to internal components within the receiver (e.g., mixers, oscillators, clocks, analog-digital converters (ADC)) that introduce spurious products into the digitization of a received RF signal. The receiver system precisely duplicates each introduced spurious product based on the reference frequencies and filters out each corresponding spurious product out of the digitized signal. Individualized canceler circuits for each introduced spurious product adjust the corresponding duplicate spurious products to cancel out the introduced spurious product from the digitized signal, resulting in an output signal free of self-generated interference.

I claim: 
     
       1. A spur canceler circuit for a signal receiver system, comprising:
 at least one frequency generator configured to:
 generate at least one reference frequency associated with a plurality of receiver components of the receiver system, the plurality of receiver components capable of introducing a plurality of spurious products into a signal received by the receiver system, the plurality of receiver components including an analog-digital converter (ADC) configured to generate a digitized signal based on the received signal and capable of introducing a first spurious product, the plurality of receiver components of the receiver system including at least one internal clock capable of introducing a second spurious product, the plurality of receiver components including an oscillator capable of introducing a third spurious product, wherein the first spurious product, the second spurious product, and the third spurious product are generated based on the at least one reference frequency, one or more harmonic orders, and one or more cross-products, the at least one reference frequency, the one or more harmonic orders, and the one or more cross-products being stored in memory to allow exact duplication, 
 and 
 generate a plurality of duplicate spurious products based on the at least one reference frequency, the one or more harmonic order, and the one or more cross-products, a first duplicate spurious product of the plurality of duplicate spurious products corresponding to the first spurious product, a second duplicate spurious product of the plurality of duplicate spurious products corresponding to the second spurious product, a third duplicate spurious product of the plurality of duplicate spurious products corresponding to the third spurious product; 
 and 
 at least one canceler circuit configured to: 
 receive the plurality of digitized signals corresponding to the received signal and including the plurality of introduced spurious products; 
 for each introduced spurious product, 1) isolate the introduced spurious product from the digitized signal and 2) adjust the corresponding duplicate spurious product to cancel out the introduced spurious product from the digitized signal; 
 and 
 generate a desired output signal free of the introduced spurious products by adding each adjusted duplicate spurious product to the digitized signal. 
 
 
     
     
       2. The spur canceler circuit of  claim 1 , wherein each duplicate spurious product is selected from a group including:
 a generated reference frequency; 
 a multiple of a reference frequency; 
 or 
 a cross product of two or more reference frequencies. 
 
     
     
       3. The spur canceler circuit of  claim 1 , wherein the at least one canceler circuit is configured for at least one of:
 adjusting an amplitude of the duplicate spurious product to align with an amplitude of the corresponding introduced spurious product; 
 or 
 adjusting a phase of the duplicate spurious product to oppose a phase of the corresponding introduced spurious product. 
 
     
     
       4. A method for cancelation of internally generated spurious products from a received signal, comprising:
 receiving, via a receiver system, a transmitted signal; 
 generating, via a plurality of receiver components of the receiver system, a plurality of digitized signals based on the received signal, the plurality of digitized signals including a plurality of introduced spurious products associated with the plurality of receiver components, the plurality of receiver components including an analog-digital converter (ADC) configured to generate a digitized signal based on the received signal and capable of introducing a first internal spurious product, the plurality of receiver components of the receiver system including at least one internal clock capable of introducing a second spurious product, the plurality of receiver components including an oscillator capable of introducing a third spurious product; 
 generating, via the receiver system, at least one reference frequency associated with the plurality of receiver components, wherein the first spurious product, the second spurious product, and the third spurious product are generated based on the at least one reference frequency, one or more harmonic orders, and one or more cross-products, the at least one reference frequency, the one or more harmonic orders, and the one or more cross-products being stored in memory to allow exact duplication; 
 generating, via the receiver system, a plurality of duplicate spurious products based on the at least one reference frequency, the one or more harmonic order, and the one or more cross-products, a first duplicate spurious product of the plurality of duplicate spurious products corresponding to the first spurious product, a second duplicate spurious product of the plurality of duplicate spurious products corresponding to the second spurious product, a third duplicate spurious product of the plurality of duplicate spurious products corresponding to the third spurious product; 
 isolating, via the receiver system, each introduced spurious product from the digitized signal; 
 adjusting, via the receiver system, the duplicate spurious product corresponding to each introduced spurious product to cancel out the introduced spurious product from the digitized signal; 
 and 
 generating, via the receiver system, a desired output signal free of the plurality of introduced spurious products by adding each adjusted duplicate spurious product to the digitized signal. 
 
     
     
       5. The method of  claim 4 , wherein generating, via the receiver system, a plurality of duplicate spurious products based on the at least one reference frequency includes:
 generating the plurality of duplicate spurious products, each duplicate spurious product selected from a group including: 
 a generated reference frequency; 
 a multiple of a reference frequency; 
 or 
 a cross product of two or more reference frequencies. 
 
     
     
       6. The method of  claim 4 , wherein adjusting, via the receiver system, the duplicate spurious product corresponding to each introduced spurious product to cancel out the introduced spurious product from the digitized signal is selected from a group including:
 adjusting an amplitude of the duplicate spurious product to align with an amplitude of the corresponding introduced spurious product; 
 or 
 adjusting a phase of the duplicate spurious product to oppose a phase of the corresponding introduced spurious product.